In a vehicle, there is demand for an application configured to determine where a driver is looking at and to perform predetermined control accordingly. For example, in a case where the driver is looking at a rearview mirror, a message or an image is displayed on the rearview mirror, or in a case where the driver does not watch a meter when the driver should check the meter, a warning is issued to the driver. Upon determining such a visually recognized section, it is necessary to detect the line-of-sight direction of the driver and the face position in the space (for example, the distance from a reference position).
An example of the driver's face detector is a driver monitor including a camera. The driver monitor is a device which monitors the condition of a driver according to the face image of the driver captured by the camera and performs predetermined control such as issuing an alarm in a case where the driver is dozing off or looking aside during driving. From the face image obtained by the driver monitor, information on the line-of-sight direction can be obtained; however, information on the face position in the space cannot be obtained. Therefore, it is impossible to determine where the driver is looking at only from the face image obtained by the driver monitor.
JP 2007-230369 A discloses that the face direction (angle) and the line-of-sight direction of a driver are detected from the face image of the driver, and predetermined control (loudspeaker volume control or the like) is performed on an in-vehicle device according to them. However, since it is not possible to detect the face position in the space with this method, it is impossible to determine where the driver is looking at. In addition, each of JP 2012-208714 A and JP 2014-49023 A discloses that a detected pressed location on a touch panel is corrected according to the relative positional relationship between a user's face and the touch panel. However, also according to these literatures, it is not possible to detect the face position in the space.
As a method of detecting the face position in the space, it is conceivable to provide a plurality of cameras or to provide a dedicated sensor. However, with these methods, the number of components increases, the configuration becomes complicated, and the cost is high.